Dual fluid cartridges are used to store and dispense two fluids which must be kept separate until the time of use and then, at the time of dispensing, need to be mixed together very quickly in a precise pre-set ratio to ensure that the proper chemical reaction takes place. If the cartridge does not dispense the two fluids properly in the required pre-set ratio, the final fluid mixture may be greatly affected and may not function or adhere as required. Examples of such fluids are those that are used to create thermoset adhesives (i.e. a resin and a hardener).
Dual fluid cartridges have been used in industry for the last twenty years and, over the years, differing types of dual fluid cartridges have been developed. An example of a relatively recently developed dual fluid cartridge is the one depicted and described in U.S. Pat. No. 5,310,091, entitled “Dual Product Dispenser”, (“'091 Patent”) which is commonly owned with this application and is incorporated by reference herein. However, with such prior designs, in order to dispense the fluids within, some means of providing a large force, generally through a mechanism which provides a mechanical advantage (e.g. a caulking gun) or a pneumatic cylinder actuated mechanism, was needed. The required additional dispensing mechanism involves an extra expense and requires the user to take the extra step of loading the cartridge into the mechanism.
These prior dispensing mechanisms and cartridge arrangements have other drawbacks as well. For instance, these other mechanisms are often hard for a user to control. A case in point is with the use of a caulking gun where the handle and trigger assembly is typically eight inches or more away from the point of application, making for a dispensing mechanism that is hard to control. Another drawback of these prior mechanisms is that they generally add weight to the dispensing assembly and still require the user to apply a large amount of force.
Accordingly, there is a need for a dual fluid dispensing cartridge that is self-contained and actuated with a simple trigger that does not need an external dispensing mechanism to dispense the fluids from the cartridge.